Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
  • C08F214/18—Monomers containing fluorine
  • C08F214/26—Tetrafluoroethene
  • C08F214/265—Tetrafluoroethene with non-fluorinated comonomers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/06—Organic material
  • B01D71/30—Polyalkenyl halides
  • B01D71/32—Polyalkenyl halides containing fluorine atoms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/003—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor characterised by the choice of material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/22—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of indefinite length
  • B29C43/24—Calendering
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/04—Particle-shaped
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/92—Measuring, controlling or regulating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
  • B29C51/26—Component parts, details or accessories; Auxiliary operations
  • B29C51/266—Auxiliary operations after the thermoforming operation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/005—Shaping by stretching, e.g. drawing through a die; Apparatus therefor characterised by the choice of materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D99/00—Subject matter not provided for in other groups of this subclass
  • B29D99/0078—Producing filamentary materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
  • C08F214/18—Monomers containing fluorine
  • C08F214/26—Tetrafluoroethene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/92514—Pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/9258—Velocity
  • B29C2948/926—Flow or feed rate
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/92685—Density, e.g. per unit length or area
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C2948/00—Indexing scheme relating to extrusion moulding
  • B29C2948/92—Measuring, controlling or regulating
  • B29C2948/92504—Controlled parameter
  • B29C2948/92704—Temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
  • B29K2023/04—Polymers of ethylene
  • B29K2023/06—PE, i.e. polyethylene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2027/00—Use of polyvinylhalogenides or derivatives thereof as moulding material
  • B29K2027/12—Use of polyvinylhalogenides or derivatives thereof as moulding material containing fluorine
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
  • B29K2995/0037—Other properties
  • B29K2995/0041—Crystalline
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
  • B29K2995/0037—Other properties
  • B29K2995/0088—Molecular weight
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2007/00—Flat articles, e.g. films or sheets
  • B29L2007/007—Narrow strips, e.g. ribbons, tapes, bands
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2327/00—Polyvinylhalogenides
  • B32B2327/12—Polyvinylhalogenides containing fluorine
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates generally to poiy(ethylene
• Ethylene-tetrafLuoroethylene (ETFE)-based polymers are known in the art, and are used as linings or coatings.
• ETFE polymers are difficult to manufacture, and even more difficult to process.
• a process for making an ETFE article that is processed below the melt has high strength, is highly porous, and which may be processed into a dense form.
• One embodiment relates to a method of making a porous poly(ethylene tetrafluoroethylene) (ETFE) tape that includes (1) lubricating a poly(ethylene tetrafluoroethylene) polymer that has an average molecular weight of at least 300,000 g/mol to form a lubricated polymer and (2) subjecting the lubricated polymer to pressure at a temperature beiow the melting point of the poiy(ethylene tetrafluoroethylene) polymer to form a porous ETFE tape.
• the lubricated polymer is ram extruded at a temperature that is about 220 C C or less below the melt temperature of the ETFE polymer.
• the ETFE tape has a node and fibril structure and a porosity greater than about 10%. Additionally, the ETFE polymer has a melt enthalpy of at least 57 J/g. in some embodiments, the ETFE polymer may include from about 0.001 mol% to about 10 moi% of an additional monomer.
• a second embodiment relates to a porous ETFE article that includes a porous tape formed from an ETFE polymer that has an average molecular weight of at least about 300,000 g/mol and a melt enthalpy of at least 57 J/g, The tape has a node and fibril structure. The ETFE polymer may include from about 0.001 mol% to about 10 moi% of an additional monomer. Additionally, the ETFE tape has a thickness from about 0.01 mm to about 4 mm and a porosity greater than about 10%.
• a third embodiment relates to a porous ETFE article that includes a porous tape formed from an ETFE polymer that has an average molecular weight of at least about 300,000 g/mol.
• the ETFE polymer includes from about 0.001 mot% to about 10 mol% of an additional monomer.
• the ETFE polymer has a melt enthalpy of at least 57 J/g.
• the ETFE tape has a porosity greater than about 10%.
• a fourth embodiment relates to a method of making a porous
• poly(ethylene tetrafluoroethylene) (ETFE) membrane that includes (1) lubricating a poly(ethylene tetrafluoroethylene) polymer that has an average molecular weight of at least 300,000 g/mol to form a lubricated polymer, (2) subjecting the lubricated polymer to pressure at a temperature below the melting point of the poly(ethylene tetrafluoroethylene) polymer to form a preform, and (3) expanding the preform at a temperature below the melt temperature of the polyethylene tetrafluoroethylene) polymer to form a porous article.
• the ETFE article has a structure of nodes and fibrils.
• the lubricated ETFE polymer is ram extruded at a temperature that is about 220°C or less below the melt temperature of the ETFE polymer. The lubricant may be removed from the preform prior to
• the ETFE polymer has a melt temperature from about 260°C to about 300°C
• a fifth embodiment relates to a process for manufacturing porous ETFE membranes that includes subjecting a lubricated poly(ethylene tetrafluoroethylene) (ETFE) polymer having an average molecular weight of at least 300,000 g/mo! and a melt enthalpy of at least 57 J/g to pressure and heat below the melt temperature of the ETFE polymer to form a tape, followed by expansion of the tape below the melt temperature of the ETFE polymer to form a porous membrane.
• the subjecting step may include ram extruding the lubricated ETFE polymer at a temperature that is about 220°C or less below the melt temperature of the ETFE polymer.
• the EFTE tape may optionally be calendered at a temperature that is about 220°C or less below the melt temperature of the ETFE polymer.
• the average molecular weight of the ETFE polymer is between about 300,000 g/moi and about 20,000,000 g/mol.
• the ETFE polymer may include at least one additional comonomer,
• a sixth embodiment relates to a porous ETFE article that includes a porous membrane formed from an ETFE polymer having an average molecular weight of at least about 300,000 g/moi and a melt enthalpy of at least 57 J/g.
• the porous ETFE membrane has a node and fibril structure.
• the ETFE membrane may have a thickness less than about 1 mm.
• a seventh embodiment relates to a process for making a dense ETFE polymer article that includes calendering a poly(ethylene tetrafluoroethylene) (ETFE) polymer having an average molecular weight greater than about 300,000 g/moi and a melt enthalpy of at least 57 J/g at a temperature that is about 220°C or less below the melt temperature of the ETFE polymer, in at least one
• ETFE poly(ethylene tetrafluoroethylene)
• the calendering occurs in the absence of a lubricant.
• the ETFE polymer has a melt temperature from about 260°C to about 300°C.
• the ETFE polymer article has a porosity less than about 10%.
• An eighth embodiment relates to a dense ETFE polymer article that includes an ETFE polymer preform that has a porosity less than about 10%.
• the ETFE polymer has an average molecular weight greater than about 300,000 g/mol and a melt enthalpy of at least 57 J/g.
• the dense ETFE polymer article is in the form of a fiber.
• the EFTE polymer preform is in the form of a tape.
• a ninth embodiment relates to method for making an ETFE copolymer fiber that includes (1) subjecting an ETFE copolymer having an average molecular weight greater than about 300,000 g/moi and a melt enthalpy of at least 57 g/moi to pressure at a first temperature that is about 220°C or less below the melt temperature of the ETFE polymer to form a preform, (2) slitting the preform in a length direction, and (3) stretching the slit preform into an ETFE polymer fiber at a second temperature that is about 220°C or less below the melt temperature of the ETFE polymer.
• the ETFE polymer fiber has a porosity less than about 10%. !n at least one embodiment, the ETFE polymer includes from about 0.001 mo!% to about 10 moi% of an additional comonomer.
• FIG 1 is a differential scanning calorimetry (DSC) thermogram of the ETFE polymer of Example 1 depicting a bimodal melting distribution in accordance with one exemplary embodiment
• FIG. 2 is a scanning electron micrograph (SEM) of the surface of the porous beading article of Example 2 taken at magnification of 20,000x according to at least one exemplary embodiment
• FIG. 3 is a scanning electron micrograph (SEM) of the surface of the interior of the porous ETFE tape of Example 3 taken at a magnification of 25,000x showing a node and fibril structure in accordance with one embodiment;
• FIG. 4 is a differential scanning calorimetry (DSC) thermogram of the ETFE polymer of Example 4 according to one embodiment of the invention.
• FIG. 5 is a scanning electron micrograph (SEM) of the surface of the interior of the drawn ETFE fiber of Example 6 taken at a magnification of 50,000x in accordance with an embodiment
• FIG. 6 is an experimental data plot of Complex Viscosity , Storage Modulus (G') and Loss Modulus (G") versus Angular Frequency for the poly (ethylene tetrafluoroethylene) (ETFE) polymer of Example 1 in accordance with an embodiment
• FIG. 7 is a Flow Curve fitted to the Cross Flow Model for the poly
• ETFE ethylene tetrafluoroethylene
• ETFE refers to ethylene tetrafluoroethylene fluoropolymer or poly(ethylene tetrafluoroethylene).
• the phrases "high degree of crystallinity” or “highly crystalline” are meant to describe an ETFE polymer that has a first melt enthalpy greater than about 57 J/g as measured by differential scanning calorimetry (DSC).
• a node may be described as a larger volume of polymer, and is where a fibril originates or terminates with no clear continuation of the same fibril through the node.
• a fibril may have a width of less than about 250 nm, or less than about 150 nm.
• the term "dense” is meant to describe an ETFE polymer preform, membrane, or article that has a porosity of less than about 10%
• lubricant is meant to describe a processing aid that includes, and in some embodiments, consists of, an incompressible fluid that is not a solvent for the polymer at processing conditions.
• the fluid-polymer surface interactions are such that it is possible to create a homogenous mixture.
• cohesive is meant to describe a tape or precursor material that is sufficiently strong for further processing
• uniaxial is meant to describe a polymer, tape, membrane, preform, or article that is expanded in only one direction.
• biaxial is meant to describe a polymer, tape, membrane, preform, or article that is expanded in at least two directions.
• melting point As used herein, the terms “melting point”, “melting temperature”, and “melt temperature” are meant to define the peak of the melt endotherm as measured by differential scanning calorimetry (DSC) during the heating of the ETFE poiymer.
• DSC differential scanning calorimetry
• the invention relates to pofy(ethytene tetrafluoroethylene) (ETFE) polymers that have an average molecular weight (Mw) of at least about 300,000 g/mol and a high degree of crystallinity and tapes, membranes, fibers, and articles made therefrom, in exemplary embodiments, the average molecular weight of the ETFE poiymer is between about 300,000 g/mol and about 20,000,000 g/mol, between about 500,000 g/mol and about 20,000,000 g/mol, between about 1 ,000,000 g/moi and about 20,000,000 g/mo!, or between about 2,000,000 g/mol and about 20,000,000 g/mol.
• ETFE average molecular weight
• the crystallinity of the ETFE poiymer may be measured by differential scanning calorimetry (DSC), As used herein, the phrases “high degree of crystallinity” or “highly crystalline” are meant to describe an ETFE polymer that has a melt enthalpy greater than about 57 J/g as measured by DSC. In addition, the ETFE poiymer may contain a trace amount of at least one additional comonomer.
• the poiy(e.thylene tetrafluoroethylene) (ETFE) polymers have a melting point from about 260°C to about 300°C, It is to be noted that the terms “melting temperature”, “melt temperature”, and “melting point” may be used
• the ETFE polymer has a melting point of approximately 293°C.
• ETFE tapes, ETFE membranes, ETFE fibers, and ETFE articles may have a percent porosity that is greater than about 10%, greater than or equal to about 15%, greater than or equal to about 20%, greater than or equal to about 25%o, greater than or equal to about 30%, greater than or equal to about 35%, greater than or equal to about 40%, greater than or aqual to about 45%, greater than or equal to about 50%, greater than or equal to about 55%, greater than or equal to about 60%, greater than or equal to about 65%, greater than or equal to about 70%, greater than or equal to about 75%, greater than or equal to about 80%, greater than or equal to about 85%, or up to (and including) 90%.
• the ETFE tape, membrane, fiber, or article may have a percent porosity from about 10% to about 90%, from about 25% to about 90%, from about 30% to about 90%, from about 40% to about 90%, from about 50% to about 90%, or from about 60% to about 90%, from about 25% to about 75%, or from about 25% to about 50%.
• the ETFE resin may be provided in a particulate form, for example, in the form of a powder.
• ETFE powders are formed of individual ETFE particles having a particle size less than about 500 nm.
• the particle size, shape, and distribution thereof are important to obtain the desired porous structures. These particle characteristics affect the packing density as well as connection density, thereby affecting the porous structures that can be produced from the ETFE particles.
• the ETFE polymer is first mixed with a lubricant, such as a light mineral oil.
• a lubricant such as a light mineral oil.
• suitable lubricants include aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, and the like, and are selected according to
• lubricant as used herein, is meant to describe a processing aid consisting of an incompressible fluid that is not a solvent for the polymer at the process conditions.
• the choice of lubricant is not particularly limiting and the selection of lubricant is largely a matter of safety and convenience.
• the fluid-polymer surface interactions are such that it is possible to create a
• the lubricant may be added to the ETFE polymer in a ratio 1 ml/100 g to about 100 ml/100 g or from about 10 mi/100 g to about 70 mi/100 g,
• the mixture is maintained beiow the melt temperature of the ETFE polymer for a period of time sufficient to wet the interior of the clusters of the ETFE poiymer with the lubricant.
• a "sufficient period of time” may be described as a time period sufficient for the ETFE particles to return to a free-flowing powder. It is to be noted that prior to wetting the interior of the ETFE poiymer clusters, the lubricant/polymer mixture is a wet, viscous mass.
• the mixture is heated to a temperature below the melt temperature of the ETFE polymer or the boiling point of the lubricant, whichever is tower. It is to be appreciated that various times and temperatures may be used to wet the ETFE polymer so long as the lubricant has a sufficient time to adequately wet the interior of the ETFE polymer clusters.
• the ETFE polymer particles can be formed into solid shapes, (e.g., fibers, tubes, tapes, sheets, and/or three dimensional self- supporting structures) without exceeding the melt temperature of the ETFE poiymer.
• the lubricated particles are heated to a point below the melting temperature of the poiymer and with the application of sufficient pressure and shear to form inter-partic!e connections and create a solid form.
• Non-limiting examples of methods of applying pressure and shear include ram extrusion (e.g., typically called paste extrusion or paste processing when lubricant is present) and optional calendering to form a cohesive, flexible, porous tape having a node and fibril structure.
• the lubricated ETFE poiymer is ram extruded to produce a cohesive, flexible, porous tape having a node and fibril structure.
• cohesive is meant to describe a tape that is sufficiently strong for further processing.
• the extrusion occurs at a temperature that is about 220°C or less below the meit temperature of the ETFE poiymer. In some embodiments, the extrusion occurs at a temperature that is about 200°C or less, or that is about 100°C or less, below the melt temperature of the ETFE polymer.
• the ETFE tape has an indeterminate length and a thickness less than about 4 mm.
• Tapes may be formed that have a thickness from about 0.01 mm to about 4 mm, from about 0.01 mm to about 3 mm, from about 0.01 mm to about 2 mm, from about 0.01 mm to about 1 mm, from about 0.08 mm to about 0.5 mm, or from 0.05 mm to 0.2 mm, or even thinner, in at least one embodiment, the ETFE tape has a thickness from about 0.05 mm to about 0.2 mm.
• the lubricant may be removed from the porous ETFE tape.
• the iubricant may be removed by washing the tape in hexane or other suitable solvent.
• the wash solvent is chosen to have excellent solubility for Iubricant and sufficient volatility to be removed below the melting point of the resin. If the iubricant is of sufficient volatility, the iubricant may be removed without a washing step, or it may be removed by heat and/or vacuum.
• the ETFE tape is then optionally permitted to dry, typically by air drying. However, any conventional drying method may be used as long as the temperature of the sample remains below the melting point of the ETFE polymer.
• the ETFE tapes once dried, may be cut to suitable sizes for expansion. Expansion of these samples occurs at temperatures that are about 220°C or less below the melt temperature of the EPTFE polymer, about 200°C or less below the melt temperature, or about 100°C or less below the melt temperature.
• the samples may be expanded in one or more directions to form a porous membrane. Expansion, either uniaxial or biaxial, may be conducted at engineering strain rates (ERS) up to 20,000%/second, or from 1% to 20,000%/ second to form an expanded porous ETFE article (e.g., expanded ETFE membrane).
• ERS engineering strain rates
• the expanded ETFE article has a structure of nodes and fibrils. It is believed that an increase in strength concurrently occurs upon expansion.
• the increase in strength of the polymer matrix is dependent upon the strength of the tape prior to expansion, the quality of the resin (e.g. , particie size, molecular weight, distribution of particle size and/or molecular weight, degree of crystallinity, composition of polymer, and the like) the temperature at which expansion is performed, the rate of expansion, and the total amount of expansion.
• the quality of the resin e.g. , particie size, molecular weight, distribution of particle size and/or molecular weight, degree of crystallinity, composition of polymer, and the like
• the ETFE polymer may be subjected to pressure at a temperature that is about 220°C or less below the melt temperature of the ETFE polymer (e.g., calendered) without the addttion of a lubricant to form a dense preform (e.g., a dense ETFE tape).
• the preform may be subsequently slit in a length direction and stretched to form a dense ETFE fiber.
• the dense preform and the dense fiber have a porosity less than about 10%.
• Thickness was measured by placing the sample between the two plates of a Miyutoyo thickness gauge (Miyutoyo Corporation, Kawasaki, Japan). The average of the multiple measurements was reported.
• Density was used to calculate the percent porosity of expanded materials using 1.8 g/cc as the full density of the sample. The volume of each sample was determined. Each sample was weighed using an AND Model HF 400 balance, and then the thickness of the samples was taken using a Miyutoyo thickness gauge (Miyutoyo Corporation, Kawasaki, Japan). Using this data, a density of the sampie can be calculated with the following formula:
• the SEM samples were imaged at 1.0 to 3,0 kV using an Hitachi SU 8000 Field Emission scanning electron microscope with mixed Upper and Lower Second Electron detectors.
• DSC data were collected using a TA instruments Q2000 DSC between -50°C and 350°C using a heating rate of 10 °C/min. Approximately 5 to 10 mg of the sample was placed into a standard Tzero pan and lid combination available from TA Instruments. A linear integration method from 200°C to 310°C was used to integrate to obtain the first melt enthalpy data.
• ETFE tetrafluoroethylene
• FIG. 6 shows such a plot for the poly (ethylene tetrafluoroethylene) (ETFE) polymer of Example 1.
• the molecular weight ⁇ Mw of the poly (ethylene tetrafluoroethylene) (ETFE) polymer of Example 1 was calculated to be 9,998,000 g/moL
• the KMnO4 injection rate was lowered to 12 g/min. After a total of 600 kPa of pressure drop was observed, the KM n O 4 injection rate was lowered to 8 g/min. After a total of 1000 kPa of pressure drop was observed, the KMnO4 injection was stopped.
• the total polymerization time was 115 min.
• the weight of the dispersion produced was 36.44 kg containing 19.44% solids.
• the dispersion was coagulated with nitric acid and dried at 130°C.
• the raw dispersion particle size (RDPS) of the polymer particle was 0.272 microns.
• the density of the poly (ethylene tetrafluoroethylene) (ETFE) polymer was measured by helium pycnometry and was determined to be 1.80 g/cc.
• a differential scanning calorimetry (DSC) thermogram of the ETFE polymer is shown in FIG. 1.
• a bimodal melting distribution was observed, with the peak of the lower melt temperature occurring at 27Q°C and a higher melt temperature occurring at 293°C.
• the melt enthalpy was determined to be 71 J/g.
• the extrudate was dried for 1 hour at 150°C in a convection oven.
• the resultant beading article had a density of 1.26 g/cc.
• the porosity of the beading article was determined to be 30%.
• a scanning electron micrograph (SEM) of the surface of the interior of the porous beading article taken at a magnification of 20,000x is shown in FIG. 2.
• the SEM shows that the beading article has a structure of nodes 10 and fibrils 20.
• the ETFE tape was dried overnight at 150°C in a convection oven.
• the porous ETFE tape had a density of 1.05 g/cc.
• the porosity of the tape was determined to be 40%.
• a scanning electron micrograph (SEM) of the surface of the interior of the porous ETFE tape taken at a magnification of 25,000x is shown in FIG. 3.
• the ETFE tape has a structure of nodes 10
• the total polymerization time was 118 min.
• the weight of the dispersion produced was 35.81 kg containing 13.81% solids.
• the dispersion was coagulated with nitric acid and dried at 130X.
• the raw dispersion particle size (RDPS) of the polymer particle was determined to be 0.181 microns.
• the density of the poly (ethylene tetrafluoroethylene) (ETFE) polymer was measured by helium pycnometry and was determined to be 1.75 g/cc.
• a differential scanning caiorimetry (DSC) thermogram of the ETFE polymer is shown in FIG. 4. As shown in FIG. 4, the melt temperature of the ETFE polymer is about 293°C. The melt enthalpy was determined to be 74 J/g.
• a one quarter inch strip from the ETFE tape of Example 5 was cut in the machine direction. This strip was then heated at 150°C for 15 minutes. Starting from a gage length of 25.4 mm, the material was stretched to 56 mm at a rate of 5000 mm/s, giving an expansion ratio of 2.2:1 to form an ETFE fiber.
• FIG. 5 A scanning electron micrograph (SEM) of the surface of the interior of the drawn ETFE fiber taken at a magnification of 50,0Q0x of the drawn ETFE fiber is shown in FIG, 5,

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